Simplify the following expression: $y = \dfrac{4n + 9}{2n + 7} - \dfrac{-3n}{2n + 7}$
Explanation: Since the expressions have the same denominator we simply subtract the numerators: $y = \dfrac{4n + 9 - (-3n)}{2n + 7}$ Distribute the negative sign: $y = \dfrac{4n + 9 + 3n}{2n + 7}$ Combine like terms: $y = \dfrac{7n + 9}{2n + 7}$